I have my doubts about resistance. That's mainly a competition thing, like in judo: not wanting to be thrown. The attacker attitude is not 'not being beaten', but to beat up the other guy. So, attackers tend to be very aggressively offensive, not defensive at all.
An aikido that aims for "realism" should base its solutions on that.

Thinking of this thread, and the atemi one, I made a short film yesterday after class, trying some atemi applications and a couple of aikido techniques in a way that I regard as "realistic".
No doubt, that will be questioned